Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2014
A Raman spectroscopic study of uranyl minerals from Cornwall, UK
R J P Driscoll,a D Wolverson,∗a J M Mitchels,a J M Skelton,a S C Parker,a M Molinari,a I Khan,b D Geeson,b and G C Allenc
Received Xth XXXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX First published on the web Xth XXXXXXXXXX 200X DOI: 10.1039/b000000x
SUPPORTING INFORMATION
a University of Bath, Claverton Down, Bath, UK. ∗ Fax: XX XXXX XXXX; Tel: XX XXXX XXXX; E-mail: [email protected] b AWE, Aldermaston, Reading, UK. c Interface Analysis Center, University of Bristol, Bristol, UK.
1–17 | 1 1 Physical appearance of the uranyl mineral samples
Autunite from Merrivale Quarry appears as fine, yellow crystals on a white, grey and black background rock, approximately 6 cm in diameter. Torbernite from Bunny Mine appeared as small (approximately 600 µm across), green, tabular crystals on a grey and brown primary rock, approximately 11 cm in diameter. Nova´cekite˘ from Wheal Edward was present as yellow and green flakes on a black and brown primary rock, approximately 5 cm across. Zeunerite from Wheal Gorland appeared as fine green crystals on a light brown background rock, approx- imately 7 cm across. Phosphuranylite from Wheal Edward occurred as a yellow crust on a brown rock (approximately 7 cm across), with fine, green associated crystals. Andersonite and schrockingerite,¨ both from Geevor Mine, are present as yellow mineral deposits on a brown background rock (both around 4 cm across); both samples have a thin layer of transparent gypsum crystals associated with the uranyl mineral. Johannite from Geevor Mine is present as pale green crystals on a yellow-brown background rock, ap- proximately 5 cm across. Natrozippeite mineral from Geevor Mine occurs as a yellow crust on a black and brown primary rock (about 7 cm across); it is associated with small, green crystals that do not contain a uranyl cation. Uranophane from Wheal Edward is present as a pale yellow crust on a light brown primary rock sample (approximately 7 cm across); it is associated with a black vein of pitchblende. Kasolite from Loe Warren Zawn occurs as an orange-red crust on one face of a large grey primary rock sample, approximately 12 cm across. Compreignacite and cuprosklodowskite were present as dark yellow and green crystals, respectively, on the same sample of brown, black and grey rock from West Wheal Owles.
2 Raman peak tables and wavelength comparisons
The tables shown in this section detail the vibrational bands seen in the Raman spectra for each mineral in this investigation. The positions given are an average of the same band seen in multiple spectra of the same sample, and both the standard deviation and the number of spectra in which each peak is seen are given. Literature bands are given; these have typically been deconvoluted. The assignment is based upon that given for the published spectra. The figures shown here illustrate the Raman spectra collected using all three excitation wavelengths for each mineral.
2 | 1–17 Fig. SI 1 A comparison of the three laser wavelengths for the uranyl phosphate mineral autunite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 1 Raman spectral bands for the uranyl phosphate mineral autunite
This Study Literature 2 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 193 † 1.7 31 190, 222 Lattice Vibrations 2+ 283 * 4.2 19 291 v2(UO2) bend 3− – – – 399, 406, 439, 464 v2(PO4) bend 3− – – – 629 v4(PO4) bend 2+ 830 3.6 60 816, 822, 833 v1(UO2) symm. stretch 2+ 899 * 4.93 9 – v3(UO2) antisymm. stretch 990 2.67 21 988 3− 1001 § 7.53 31 1007 v3(PO4) symm. stretch 1008 4.16 21 1018
Sixty individual spectra were analysed for this sample of autunite. * Low intensity or broad bands, not always visible in spectra. † The 193 cm−1 peak was most prominent within the 785 nm spectra. § The 1001 cm−1 peak was only visible when the 990 and 1008 cm−1 peaks were not.
1–17 | 3 Fig. SI 2 A comparison of the three laser wavelengths for the uranyl phosphate mineral torbernite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 2 Raman spectral bands for the uranyl phosphate mineral torbernite
This Study Literature 2 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 191 * 2.3 26 – Lattice Vibrations 2+ – – – 222, 290 v2(UO2) bend 404 * 2.7 24 399, 406, 439, 464 v (PO )3− bend 440 * 3.9 9 2 4 3− – – – 629 v4(PO4) bend 2+ 825 1.8 38 808, 826 v1(UO2) symm. stretch 2+ 903 * 2.1 10 900 v3(UO2) antisymm. stretch 3− 992 1.75 38 957, 988, 995, 1004 v3(PO4) antisymm. stretch
Thirty eight individual spectra were analysed for this sample of torbernite. * Low intensity or broad bands, not always visible in spectra.
4 | 1–17 Fig. SI 3 A comparison of the three laser wavelengths for the uranyl arsenate mineral novacekite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 3 Raman spectral bands for the uranyl arsenate mineral nova´cekite˘
This Study Literature 10 Literature 2 Position Standard Number Saleeite´ Peak Attribution (cm−1) Deviation of spectra Positions (cm−1) 185 2.9 28 177, 196 – Lattice Vibrations 2+ 269 * 6.0 10 218, 234, 283 284 v2(UO2) bend 3− 325 * 4.3 14 v2(PO4) bend 452 * 2.6 10376, 405, 446, 471 389 or 3− 471 * 5.5 8 v2(AsO4) bend 3− – – – 573, 612 643 v4(PO4) bend 2+ 817 2.6 55 827, 843 818, 833, 847 v1(UO2) symm. stretch 2+ 889 5.6 36 896 – v3(UO2) antisymm. stretch 989 2.3 11 980, 994, 1007 982, 988, 1007 v (PO )3− antisymm. stretch 1034 * 2.6 7 3 4
Fifty five individual spectra were analysed for this sample of nova´cekite.˘ No literature spectra are available for a direct comparison with nova´cekite,˘ so its spectrum has been compared against saleeite,´ its phosphate analogue. * Low intensity or broad bands, not always visible in spectra.
1–17 | 5 Fig. SI 4 A comparison of the three laser wavelengths for the uranyl arsenate mineral zeunerite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 4 Raman spectral bands for the uranyl arsenate mineral zeunerite
This Study Literature 11 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) – – – 182 Lattice Vibrations 2+ – – – 218, 235, 275 v2(UO2) bend 3− 323 * 4.9 5 320, 380 v2(AsO4) bend 404 * 4.6 7 396 v (AsO )3− bend 463 6.6 19 446, 463 4 4 2+ 821 3.0 25 811, 818 v1(UO2) symm. stretch 2+ 886 4.5 16 890 v3(UO2) antisymm. stretch 987 1.7 9 – unknown 1029 * 2.8 4 – unknown
Twenty five individual spectra were analysed for this sample of zeunerite. * Low intensity or broad bands, not always visible in spectra.
6 | 1–17 Fig. SI 5 A comparison of the three laser wavelengths for the uranyl phosphate mineral phosphuranylite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 5 Raman spectral bands for the uranyl phosphate mineral phosphuranylite
This Study Literature 4 Minerva Saddle Ruggles Attribution Position Standard Number Heights Ridge Mine (cm−1) Deviation of spectra Position (cm−1) 148 * 2.3 16 111, 152, 175 117, 145, 166 112, 147, 161 Lattice Vibrations 216 * 4.2 13 211 205 208 239 * 3.7 5 220 227, 240 238 2+ 260 * 3.9 13 263 267 267 v2(UO2) bend 283 * 3.4 5 294 287 295 312 * 5.3 6 3− 435 6.0 25 404, 435, 452 368, 394, 417, 439 396, 398, 421, 437, 452, 476 v2(PO4) bend 3− 558 * 2.7 7 564, 613, 655 500, 532, 566 511, 515, 536, 569, 616 v4(PO4) bend 2+ 801 4.9 29 768, 793, 805, 815 816, 837, 843, 847 812, 817, 832, 841 v1(UO2) symm. stretch 2+ – – – – – 894 v3(UO2) antisymm. stretch 992 † 2.8 10 992 1009 1005 3− 1017 † 1.2 8 1016 1050 1032, 1050, 1055 v3(PO4) antisymm. stretch – – – 1122 1125 1124
Twenty nine individual spectra were analysed for this sample of phosphuranylite. * Low intensity or broad bands, not always visible in spectra. † The 992 and 1017 cm−1 bands appear together, in a small number of 785 nm spectra.
1–17 | 7 Fig. SI 6 A comparison of the three laser wavelengths for the uranyl carbonate mineral andersonite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 6 Raman spectral bands for the uranyl carbonate mineral andersonite
This Study Literature 3 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 130 3.1 7 164, 182 Lattice Vibrations 225 * 5.2 8 224, 242, 284, 299 v (UO )2+ bend 291 * 3.3 6 2 2 2− 743 * 2.0 4 697, 732, 744 v4(CO3) bend 2+ 833 0.5 15 830, 833 v1(UO2) symm. stretch 2− 1092 2.3 15 1080, 1092 v1(CO3) symm. stretch 2− – – – 1370, 1406 v3(CO3) antisymm. stretch
Fifteen individual spectra were analysed for this sample of andersonite. * Low intensity or broad bands, not always visible in spectra.
8 | 1–17 Fig. SI 7 A comparison of the three laser wavelengths for the uranyl carbonate mineral schrockingerite.¨ The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 7 Raman spectral bands for the uranyl carbonate mineral schrockingerite¨
This Study Literature 6 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) – – – 157 Lattice Vibrations 253 * 0.5 3 308 v (UO )2+ bend 307 * 2.9 4 2 2 416 * 3.8 5 471 v (SO )2− bend 496 * 3.6 6 2 4 2− 743 2.1 16 707, 742 v4(CO3) bend 2+ 815 1.0 21 815 v1(UO2) symm. stretch 984 2.0 14 983 v (SO )2− symm. stretch 1009 * 0.8 12 1 4 2− 1093 1.8 12 1092 v1(CO3) symm. stretch 2− 1136 3.3 9 1090, 1100, 1147 v3(SO4) antisymm. stretch
Twenty one individual spectra were analysed for this sample of schrockingerite.¨ * Low intensity or broad bands, not always visible in spectra.
1–17 | 9 Fig. SI 8 A comparison of the three laser wavelengths for the uranyl sulphate mineral johannite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 8 Raman spectral bands for the uranyl sulphate mineral johannite
This Study Literature 9 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) – – – 184 Lattice Vibrations 203 * 3.0 13 205 v (UO )2+ bend 244 * 2.4 10 277 2 2 – – – 302 Cu-O stretch 2− 352 * 0.8 6 384 v2(SO4) bend 2− 448 * 1.7 7 481, 539 v4(SO4) bend 2+ 836 1.1 30 756, 788, 812 v1(UO2) symm. stretch 2+ – – – 948, 975 v3(UO2) antisymm. stretch 2− 1045 1.3 14 1042 v1(SO4) symm. stretch 2− 1095 3.1 18 1009, 1100, 1147 v3(SO4) antisymm. stretch
Thirty individual spectra were analysed for this sample of johannite. * Bands are only visible in a number of 532 and 785 nm spectra.
10 | 1–17 Fig. SI 9 A comparison of the three laser wavelengths for the uranyl sulphate mineral natrozippeite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 9 Raman spectral bands for the uranyl sulphate mineral natrozippeite
This Study Literature 5 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 191 * 1.1 16 196 Lattice Vibrations 2+ 250 * 2.1 10 250 v2(UO2) bend 2− 397 1.8 28 373, 398, 431, 498 v2(SO4) bend 2− – – – 669 v4(SO4) bend 2+ 840 4.5 38 813, 823, 834, 840, 841 v1(UO2) symm. stretch 2− 1013 0.7 21 980, 1007, 1010 v1(SO4) symm. stretch 1094 * 1.5 15 1081, 1091, 1130 v (SO )2− antisymm. stretch 1159 * 4.1 12 3 4
Thirty eight individual spectra were analysed for this sample of natrozippeite. No information was forthcoming from the 532 nm spectra, as a fluorescence band drowned the region under investigation. The wavelength that gave the best spectra was 785 nm. * Bands are not consistently visible in all spectra.
1–17 | 11 Fig. SI 10 A comparison of the three laser wavelengths for the uranyl silicate mineral uranophane. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 10 Raman spectral bands for the uranyl silicate mineral uranophane
This Study Literature 7 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 209 * 2.8 13 213, 250, 280, 288, 324 v (UO )2+ bend 283 * 3.4 6 2 2 4− 399 * 2.0 6 398, 469 v2(SiO4) bend 4− 544 * 0.9 6 544 v4(SiO4) bend 2+ 800 1.4 21 711, 786, 792, 796 v1(UO2) symm. stretch 2+ 856 * 1.7 3 – v3(UO2) antisymm. stretch 4− 961 3.5 16 960, 963 v3(SiO4) antisymm. stretch
Twenty one individual spectra were analysed for the sample of uranophane. * Bands are not consistently visible in all spectra.
12 | 1–17 Fig. SI 11 A comparison of the three laser wavelengths for the uranyl silicate mineral cuprosklodowskite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 11 Raman spectral bands for the uranyl silicate mineral cuprosklodowskite
This Study Literature 7 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 203 2.4 13 205, 217 273 * 3.1 5 267, 276 v (UO )2+ bend 299 * 1.0 5 2 2 301 312 * 0.9 3 4− 384 * 0.5 3 411, 476 v2(SiO4) bend 4− – – – 507, 535 v4(SiO4) bend 2+ 792 1.6 19 746, 758, 774, 787 v1(UO2) symm. stretch 2+ 919 * 2.0 6 – v3(UO2) antisymm. stretch 4− 974 2.1 13 974 v3(SiO4) antisymm. stretch
Nineteen individual spectra were analysed for the sample of cuprosklodowskite. * Bands are not consistently visible in all spectra.
1–17 | 13 Fig. SI 12 A comparison of the three laser wavelengths for the uranyl silicate mineral kasolite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 12 Raman spectral bands for the uranyl silicate mineral kasolite
This Study Literature 7 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 196 8.5 8 154, 165, 185 Lattice Vibrations 2+ 230 0.5 8 217, 231, 234, 285, 302 v2(UO2) bend 4− 415 * 1.0 3 415, 454 v2(SiO4) bend 4− – – – 501, 533, 575 v4(SiO4) bend 2+ 760 0.5 9 721, 750, 758, 766, 793 v1(UO2) symm. stretch 2+ 904 0.9 8 903 v3(UO2) antisymm. stretch 4− 939 0.9 6 – v3(SiO4) antisymm. stretch
Nine individual spectra were analysed for this sample of kasolite. * Bands are not consistently visible in all spectra.
14 | 1–17 Fig. SI 13 A comparison of the three laser wavelengths for the uranyl hydrate mineral compreignacite. The left figure shows the raw spectra. Each section of the spectra shown on the right have been rescaled, separately, to emphasise the bands.
Table SI 13 Raman spectral bands for the uranyl silicate mineral compreignacite
This Study Literature 8 Position Standard Number Position Attribution (cm−1) Deviation of spectra (cm−1) 164 * 3.0 6 153 Lattice Vibrations 2+ 204 * 1.9 7 197, 253 v2(UO2) bend 329 * 5.3 10 – unknown 402 * 3.7 8 439 v(U3O) stretch) 460 * 5.0 12 – unknown U-O-H bend and 549 1.1 7 602, 687 water liberation 2+ 834 † 4.24 38 824, 848 v1(UO2) symm. stretch 1010, 1050, 1080, 1110, ––– U-O-H bending 1160, 1190, 1330, 1454
Thirty eight individual spectra were analysed for this sample of compreignacite. * Bands are not consistently visible in all spectra. † A smaller peak or shoulder is sometimes present about 804 cm−1 in 785 nm spectra, or about 858 cm−1 in 325 nm spectra.
1–17 | 15 3 Analysis of the EDX data
Table SI 14 The EDX analysis of the minerals in this investigation Atomic Percentage (±1%), averaged over multiple spectra Mineral Name U O P As Si S Cu Ca Mg Na K Pb F Autunite 7.5 81.1 5.9 0.8 3.7 Torbernite 8.3 80.3 7.6 0.2 3.7 Nova´cekite˘ 6.3 86.8 0.9 3.8 2.2 Zeunerite 8.4 80.0 1.7 6.3 3.6 Phosphuranylite 8.7 77.5 5.5 0.4 3.8 2.2 Andersonite 3.2 74.4 4.1 9.6 3.2 5.5 Schrockingerite¨ 4.9 69.5 4.1 13.7 2.6 5.1 Johannite 6.1 80.4 2.0 5.6 4.2 Natrozippeite 12.2 77.1 5.6 5.1 Uranophane 7.5 80.7 7.7 3.0 Cuprosklodowskite 7.3 77.1 1.5 1.4 9.2 2.6 Kasolite 7.1 76.4 7.0 6.8 Compreignacite 12.1 80.7 1.9 3.0 2.3
Carbon is not shown in the EDX, as the percentage is too high to reliably predict the mineral composition. This is likely due to the presence of carbon in the background rock and the carbon tape used to mount the sample. The percentage values shown here only consider the elements present in significant quantites; any elements that were present below 1% have not been included in this table and may be considered as part of the background rock. The concentration of uranium is typically slightly higher than expected from the ratio of polyanion, which may be explained by the presence of uranium in the background rock. The only difference to this is for the uranyl silicates, where the silicon ratio tends to be higher than the uranium. However, silicon was seen in trace quantities for almost all spectra, often alongside aluminium and other elements. Overall, the ratios of uranium to polyanion generally agree with literature values. The layered structure seen in the majority of minerals allows for cations to move through the interlayer space, which may account for the cation ratio variation in different samples. A cation deficiency is seen in natrozippeite, uranophane, cuprosklodowskite and compreignacite. The most significant deviation from theoretical composition are seen in the uranyl carbonate mineral andersonite. The theoretical formula has a 2:1 ratio of sodium:calcium, whereas the EDX seen here contains significantly more calcium, alongside the unexpected presence of sulphur 1 and fluorine. These elements may be explained by the presence of gypsum (CaSO4, reported by Elton and Hooper ) and perhaps fluorspar (CaF2), which are both common components of gangue (the host-rock).
Table SI 15 Estimation of the chemical composition for the minerals in this investigation, based on the EDX spectra Mineral Theoretical Composition Estimate from EDX Autunite Ca(UO2)2(PO4)2·11H2O Ca(UO2)2(PO4)1.6(AsO4)0.2 Torbernite Cu(UO2)2(PO4)2·12H2O Cu0.9(UO2)2(PO4)1.8 Zeunerite Cu(UO2)2(AsO4)2·12H2O Cu0.9(UO2)2(PO4)0.4(AsO4)1.5 Nova´cekite˘ Mg(UO2)2(AsO4)2·12H2O Mg0.7(UO2)2(PO4)0.3(AsO4)1.2 Phosphuranylite Ca(UO2)3(PO4)2(OH)2·6H2OK0.7Ca1.3(UO2)3(PO4)1.9 Andersonite Na2Ca(UO2)(CO3)3·6H2O NaCa3(UO2)(SO4)1.3F1.7 Schrockingerite¨ NaCa3(UO2)(CO3)3(SO4)F·10H2O Na0.5Ca2.8(UO2)(SO4)0.8 Johannite Cu(UO2)2(OH)2(SO4)2·8H2O Cu1.4(UO2)2(SO4)1.8 Natrozippeite Na5(UO2)8(SO4)4O5,(OH)3·8H2O Na2.5(UO2)6(SO4)2.7 Uranophane Ca(UO2)2(SiO4)2·5H2O Ca0.8(UO2)2(SiO4)2.1 Kasolite Pb(UO2)(SiO4)·2H2O Pb(UO2)(SiO4 Cuprosklodowskite Cu(UO2)2(SiO4)2·6H2O Cu0.7(UO2)2(SiO4)2.5 Compreignacite K2(UO2)6O4(OH)6·7H2OK1.2(UO2)6
16 | 1–17 References
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